Commit 8428e5ad authored by Dave Gerlach's avatar Dave Gerlach Committed by Santosh Shilimkar
Browse files

memory: ti-emif-sram: introduce relocatable suspend/resume handlers 



Certain SoCs like Texas Instruments AM335x and AM437x require parts
of the EMIF PM code to run late in the suspend sequence from SRAM,
such as saving and restoring the EMIF context and placing the memory
into self-refresh.

One requirement for these SoCs to suspend and enter its lowest power
mode, called DeepSleep0, is that the PER power domain must be shut off.
Because the EMIF (DDR Controller) resides within this power domain, it
will lose context during a suspend operation, so we must save it so we
can restore once we resume. However, we cannot execute this code from
external memory, as it is not available at this point, so the code must
be executed late in the suspend path from SRAM.

This patch introduces a ti-emif-sram driver that includes several
functions written in ARM ASM that are relocatable so the PM SRAM
code can use them. It also allocates a region of writable SRAM to
be used by the code running in the executable region of SRAM to save
and restore the EMIF context. It can export a table containing the
absolute addresses of the available PM functions so that other SRAM
code can branch to them. This code is required for suspend/resume on
AM335x and AM437x to work.

In addition to this, to be able to share data structures between C and
the ti-emif-sram-pm assembly code, we can automatically generate all of
the C struct member offsets and sizes as macros by processing
emif-asm-offsets.c into assembly code and then extracting the relevant
data as is done for the generated platform asm-offsets.h files.

Acked-by: default avatarTony Lindgren <tony@atomide.com>
Acked-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarDave Gerlach <d-gerlach@ti.com>
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@oracle.com>
parent 12bb14aa

drivers/memory/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -84,6 +84,16 @@ config OMAP_GPMC_DEBUG 
	  bootloader or else the GPMC timings won't be identical with the

	  bootloader timings.



config TI_EMIF_SRAM

	tristate "Texas Instruments EMIF SRAM driver"

	depends on (SOC_AM33XX || SOC_AM43XX) && SRAM

	help

	  This driver is for the EMIF module available on Texas Instruments

	  AM33XX and AM43XX SoCs and is required for PM. Certain parts of

	  the EMIF PM code must run from on-chip SRAM late in the suspend

	  sequence so this driver provides several relocatable PM functions

	  for the SoC PM code to use.



config MVEBU_DEVBUS

	bool "Marvell EBU Device Bus Controller"

	default y

drivers/memory/Makefile

+8 −0
Original line number Diff line number Diff line
@@ -23,3 +23,11 @@ obj-$(CONFIG_DA8XX_DDRCTL) += da8xx-ddrctl.o 


obj-$(CONFIG_SAMSUNG_MC)	+= samsung/

obj-$(CONFIG_TEGRA_MC)		+= tegra/

obj-$(CONFIG_TI_EMIF_SRAM)	+= ti-emif-sram.o

ti-emif-sram-objs		:= ti-emif-pm.o ti-emif-sram-pm.o



AFLAGS_ti-emif-sram-pm.o	:=-Wa,-march=armv7-a



include drivers/memory/Makefile.asm-offsets



drivers/memory/ti-emif-sram-pm.o: include/generated/ti-emif-asm-offsets.h

drivers/memory/Makefile.asm-offsets

0 → 100644
+5 −0
Original line number Diff line number Diff line 
drivers/memory/emif-asm-offsets.s: drivers/memory/emif-asm-offsets.c

	$(call if_changed_dep,cc_s_c)



include/generated/ti-emif-asm-offsets.h: drivers/memory/emif-asm-offsets.s FORCE

	$(call filechk,offsets,__TI_EMIF_ASM_OFFSETS_H__)

drivers/memory/emif-asm-offsets.c

0 → 100644
+92 −0
Original line number Diff line number Diff line 
/*

 * TI AM33XX EMIF PM Assembly Offsets

 *

 * Copyright (C) 2016-2017 Texas Instruments Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation version 2.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/ti-emif-sram.h>



int main(void)

{

	DEFINE(EMIF_SDCFG_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_sdcfg_val));

	DEFINE(EMIF_TIMING1_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_timing1_val));

	DEFINE(EMIF_TIMING2_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_timing2_val));

	DEFINE(EMIF_TIMING3_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_timing3_val));

	DEFINE(EMIF_REF_CTRL_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_ref_ctrl_val));

	DEFINE(EMIF_ZQCFG_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_zqcfg_val));

	DEFINE(EMIF_PMCR_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_pmcr_val));

	DEFINE(EMIF_PMCR_SHDW_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_pmcr_shdw_val));

	DEFINE(EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_rd_wr_level_ramp_ctrl));

	DEFINE(EMIF_RD_WR_EXEC_THRESH_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_rd_wr_exec_thresh));

	DEFINE(EMIF_COS_CONFIG_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_cos_config));

	DEFINE(EMIF_PRIORITY_TO_COS_MAPPING_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_priority_to_cos_mapping));

	DEFINE(EMIF_CONNECT_ID_SERV_1_MAP_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_connect_id_serv_1_map));

	DEFINE(EMIF_CONNECT_ID_SERV_2_MAP_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_connect_id_serv_2_map));

	DEFINE(EMIF_OCP_CONFIG_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_ocp_config_val));

	DEFINE(EMIF_LPDDR2_NVM_TIM_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_lpddr2_nvm_tim));

	DEFINE(EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_lpddr2_nvm_tim_shdw));

	DEFINE(EMIF_DLL_CALIB_CTRL_VAL_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_dll_calib_ctrl_val));

	DEFINE(EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_dll_calib_ctrl_val_shdw));

	DEFINE(EMIF_DDR_PHY_CTLR_1_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_ddr_phy_ctlr_1));

	DEFINE(EMIF_EXT_PHY_CTRL_VALS_OFFSET,

	       offsetof(struct emif_regs_amx3, emif_ext_phy_ctrl_vals));

	DEFINE(EMIF_REGS_AMX3_SIZE, sizeof(struct emif_regs_amx3));



	BLANK();



	DEFINE(EMIF_PM_BASE_ADDR_VIRT_OFFSET,

	       offsetof(struct ti_emif_pm_data, ti_emif_base_addr_virt));

	DEFINE(EMIF_PM_BASE_ADDR_PHYS_OFFSET,

	       offsetof(struct ti_emif_pm_data, ti_emif_base_addr_phys));

	DEFINE(EMIF_PM_CONFIG_OFFSET,

	       offsetof(struct ti_emif_pm_data, ti_emif_sram_config));

	DEFINE(EMIF_PM_REGS_VIRT_OFFSET,

	       offsetof(struct ti_emif_pm_data, regs_virt));

	DEFINE(EMIF_PM_REGS_PHYS_OFFSET,

	       offsetof(struct ti_emif_pm_data, regs_phys));

	DEFINE(EMIF_PM_DATA_SIZE, sizeof(struct ti_emif_pm_data));



	BLANK();



	DEFINE(EMIF_PM_SAVE_CONTEXT_OFFSET,

	       offsetof(struct ti_emif_pm_functions, save_context));

	DEFINE(EMIF_PM_RESTORE_CONTEXT_OFFSET,

	       offsetof(struct ti_emif_pm_functions, restore_context));

	DEFINE(EMIF_PM_ENTER_SR_OFFSET,

	       offsetof(struct ti_emif_pm_functions, enter_sr));

	DEFINE(EMIF_PM_EXIT_SR_OFFSET,

	       offsetof(struct ti_emif_pm_functions, exit_sr));

	DEFINE(EMIF_PM_ABORT_SR_OFFSET,

	       offsetof(struct ti_emif_pm_functions, abort_sr));

	DEFINE(EMIF_PM_FUNCTIONS_SIZE, sizeof(struct ti_emif_pm_functions));



	return 0;

}

drivers/memory/emif.h

+17 −0
Original line number Diff line number Diff line
@@ -555,6 +555,9 @@ 
#define READ_LATENCY_SHDW_SHIFT				0

#define READ_LATENCY_SHDW_MASK				(0x1f << 0)



#define EMIF_SRAM_AM33_REG_LAYOUT			0x00000000

#define EMIF_SRAM_AM43_REG_LAYOUT			0x00000001



#ifndef __ASSEMBLY__

/*

 * Structure containing shadow of important registers in EMIF
@@ -585,5 +588,19 @@ struct emif_regs { 
	u32 ext_phy_ctrl_3_shdw;

	u32 ext_phy_ctrl_4_shdw;

};



struct ti_emif_pm_functions;



extern unsigned int ti_emif_sram;

extern unsigned int ti_emif_sram_sz;

extern struct ti_emif_pm_data ti_emif_pm_sram_data;

extern struct emif_regs_amx3 ti_emif_regs_amx3;



void ti_emif_save_context(void);

void ti_emif_restore_context(void);

void ti_emif_enter_sr(void);

void ti_emif_exit_sr(void);

void ti_emif_abort_sr(void);



#endif /* __ASSEMBLY__ */

#endif /* __EMIF_H */

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